feat(web): add React Query, dark mode toggle, and error retry UX

- Install @tanstack/react-query with exponential backoff retry config
- Create QueryClientProvider and custom hooks for listings, analytics,
  payments, and subscription API calls
- Migrate 5 dashboard pages from useState/useEffect to React Query hooks
- Add dark mode CSS variables and ThemeProvider with localStorage persistence
- Add theme toggle button in dashboard header (sun/moon icon)
- Enhance error boundaries with auto-retry, retry count, and loading state

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/app/error.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import * as Sentry from '@sentry/nextjs';
-import { useEffect } from 'react';
+import { useEffect, useState } from 'react';
 
 export default function GlobalError({
   error,
@@ -10,6 +10,9 @@ export default function GlobalError({
   error: Error & { digest?: string };
   reset: () => void;
 }) {
+  const [retryCount, setRetryCount] = useState(0);
+  const [autoRetrying, setAutoRetrying] = useState(false);
+
   useEffect(() => {
     Sentry.captureException(error);
     if (process.env.NODE_ENV !== 'production') {
@@ -17,6 +20,23 @@ export default function GlobalError({
     }
   }, [error]);
 
+  // Auto-retry once after 3 seconds
+  useEffect(() => {
+    if (retryCount > 0) return;
+    setAutoRetrying(true);
+    const timer = setTimeout(() => {
+      setAutoRetrying(false);
+      setRetryCount((c) => c + 1);
+      reset();
+    }, 3000);
+    return () => clearTimeout(timer);
+  }, [error, reset, retryCount]);
+
+  const handleRetry = () => {
+    setRetryCount((c) => c + 1);
+    reset();
+  };
+
   return (
     <div className="flex min-h-screen flex-col items-center justify-center bg-background px-4">
       <div className="mx-auto max-w-md text-center">
@@ -39,19 +59,37 @@ export default function GlobalError({
           Đã xảy ra lỗi
         </h1>
         <p className="mt-2 text-muted-foreground">
-          Rất tiếc, đã có lỗi xảy ra. Vui lòng thử lại.
+          {autoRetrying
+            ? 'Đang tự động thử lại...'
+            : 'Rất tiếc, đã có lỗi xảy ra. Vui lòng thử lại.'}
         </p>
         {error.digest && (
           <p className="mt-1 text-xs text-muted-foreground">
             Mã lỗi: {error.digest}
           </p>
         )}
+        {retryCount > 0 && (
+          <p className="mt-1 text-xs text-muted-foreground">
+            Đã thử lại {retryCount} lần
+          </p>
+        )}
         <div className="mt-8 flex justify-center gap-3">
           <button
-            onClick={reset}
-            className="inline-flex h-10 items-center justify-center rounded-md bg-primary px-6 text-sm font-medium text-primary-foreground shadow transition-colors hover:bg-primary/90"
+            onClick={handleRetry}
+            disabled={autoRetrying}
+            className="inline-flex h-10 items-center justify-center rounded-md bg-primary px-6 text-sm font-medium text-primary-foreground shadow transition-colors hover:bg-primary/90 disabled:opacity-50"
           >
-            Thử lại
+            {autoRetrying ? (
+              <>
+                <svg className="mr-2 h-4 w-4 animate-spin" viewBox="0 0 24 24" fill="none">
+                  <circle className="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="4" />
+                  <path className="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z" />
+                </svg>
+                Đang thử lại...
+              </>
+            ) : (
+              'Thử lại'
+            )}
           </button>
           <a
             href="/"